Add the subscribe Widget as noted above - then send a plain email to your friends with the blog address (make sure it can be clicked on) with a note you have started a blog and they can subscribe to it if they want.
Under Dashboard >> Settings >> Reading - I select "For each article in a feed, show Summery" so if I write a large Post with a lot of pictures in it they don't get a big email - also when they read your Post you will see a view on your Stats Page.
On the bottom left corner of your Stats Page you can see a list of the email addresses that have subscribed.
Good Luck